hello sir. i have been through your article related to SPWM and it is working fine and thanks for this. But my next point is i want to change frequency as well as voltage using a potentiometer. Please reply me

If you've understood how it works, you can make it using any microcontroller. As the ATTINY13 does not have any ECCP or similar module, you need to apply the SPWM technique a little differently to generate the required outputs.

in a three-phase inverter bridge six switches. how to get the pulse train for one as create table sine of 90 ° with 19 points?. then to form the three AC waveformsI see, from 90 to 180 repeats of the 0-90 but in mirror, and then 180 to 360 would only be the opposite of the first half cycle, but when the three branches desfaso 120 and take the voltage between them do not see a way AC waveform.(in this simulation). I will use the PIC18F4431 to implement the system. You can help.also try to simulate with proteus AN900 microchip but only see PWM1-PWM3.PWM3-PWM5 And PWM5-PWM1 is not there seems to be a problem with PWM5, does not change the frequency.please, jhon90.ortiz@hotmail.es

Hello Tahmid Tour post on sine wave generator for dc-ac Sine wave Inverter was very helpful Please, Can you help with a tutorial on how to design and select a filler Inductor Core for filtering of the Sod wave Component from the spwm output . This has been a problem for me for quiet a while now. I will be very grateful for your assistance.RegardS Bello

Thanks for the support given to the implementation of the sine wave table.Question: Do you multiply the values ​​by 250 V peak breasts to get the final values ​​of the table. In my country the voltage is 220 Vrms, I would multiply the values ​​breasts (220x1.414)? . Thanks for the reply.

No, that's not for the peak voltage of the output sine wave. That's for the peak voltage of the PR2 register. It doesn't matter what your peak sine wave voltage is. That multiplication factor (250 here) is set by the value of the PR2 register and the peak value you want the sine wave table to have (usually equal to PR2).

Hi Tahmid:To clarify my concept as the correction that do not match the frequency, not quite understand, because it is not what happens with the RC2 pin state in the loop of 16 repetitions. So I wrote the following to me confirmnes if correct.

When you start to develop the sine table, say take 10 parts for 50Hz half sine wave.Then right thing would be to calculate the PWM period according to these data:1/50 = 0.02 = 20.000 us.

Then each part is worth 20,000 / 20 = 1,000 us and this value would be the PWM period. This value would be used in the formula:(PR2 +1) = PWM Period / (4x Tosc x TMR2 prescaler value)

Sorry Tahmid:To complete my question and I'm clear all the following is correct?If you say use a 16Khz carrier frequency, the period of this signal is 1/16, 000 = 62.5 us corresponding to PWM period.With this data we calculate how many pieces we will divide 50Hz half sine wave. For this we proceed as follows:1/50hz = 20,000 us20,000 us/62.5us = 320 parts into which 50Hz sine wave.Then half-wave 50Hz sine there are 160 parties and this data is constructed sine table.

So, am I right in concluding that the number "32" comes from "a fraction of comparison between carrier freq vs mains freq"?i.e if carrier freq is 6kHz and mains freq is 50Hz, then the comparison value is 120 for full cycle, or 60 for the half cycle. then we can use any fraction of that 60 for the sine table size, maybe 20,30,or 60?

Unfortunately, I don't think I can help you much with that since I have not used PICBASIC PRO. I could help you with the algorithm, but I can't help you with converting that to PICBASIC PRO code. You'll need to do that.

Hi tahmid,i designed an inverter which is transformer less.Bus Link Capacitor Voltage =800Vmax.Power =10KVAPWM Generated Using Analog Circuit.Topology =Half BridgeSwitching Frequency =10KHzCurrently i have connected RC snubber across both MOSFET & using same Bus Link Capacitor as filter capacitor also.The Driver used can Sink & Source 4A current.But i want to use anti-parallel diode across gate resistor,for fast turn off.Which Diode to choose as frequency is 10KHz?Also snubber required is across both or single in half bridge?

Please can you explain in detail the advantages of FULL BRIDGE over CENTER TAPPED inverters apart from extra coil cost. Lets assume a transformer is wound with 12SWG 25 turns at the primary for FULL BRIDGE, and the same size of transformer is used to wind 25-0-25 CENTER TAPPED with also 12SWG, what will be the difference if all other parts of the inverter is built with equal material.

HI TahmidCongratulations for your excelent blogI have already done an inverter single phase in the dsPIC BASIC PRO compiler using a dsPIC30F4012. It works ok.My question is how to generate a 3 phase inverter. What are the issues to solve? What should be added?Could you make please a tutorial to make a three phase inverter? may be using a dsPIC, provided it has the hardware (Motor Control PWM) that supports 6 outputs, for a full bridge 3 phase inverter.I hope you can spare a little time to help me and a lot of other guys interested.

On the other hand, could you please recommend a book or pdf document to consult this issue?Thanks a lot for your valuable help.

For starters you for your notes. I want to consult you.I have understood your development table for the sine wave.For your example of 10 values, with Fosc = 16Mhz, fPWM = 16kHz, results in a PR2 = 249.After analysis you tell us 62.5x20 = 1,250 us, would be rebuilding a wave of 800Hz and not what we want to 50Hz. Therefore it is repeated 16 times each value and then changed to another value and is repeated 16 times to end the last value.

Question:Can you work the way I describe below?It has 10x 16 = 160 values for a half cycle

10ms / 160 = 62.5 us ===> Tpwm

ThenFosc = 16MHz, Tosc = 62.5 nsFpwm = 16Khz, Tpwm = 62.5 us

Then PR2 = 250 and 160 entered the sine table and get the values 160 and 62.5 for each interrupt us we get a value ending with the last value.

What advantage is there as you do you implement or you can work as I have described ?

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About Me

I am Syed Tahmid Mahbub, from Dhaka, Bangladesh, born on August 1, 1994.
Electronics is my passion and from class V, I have been learning electronics. I learnt and worked mostly on SMPS, power electronics, microcontrollers and integration of microcontrollers with SMPS and power electronics. I've used PIC and AVR microcontrollers - PIC 10F, 12F, 16F, 18F, 24F, dsPIC 30F, 33F, PIC32, ATmega and ATtiny, integrating them with various SMPS and power electronics circuits.
I have completed my Bachelor's degree from Cornell University (Class of 2017) in Ithaca, New York, USA, majoring in Electrical and Computer Engineering (ECE).
I am a member of the forum www.edaboard.com, where I am an "Advanced Member Level 5" (the highest level attainable) and also the forum allaboutcircuits.com, where I am a "Senior Member". I post to help solve electronics-related problems of engineers and engineering students from all over the world.
I love watching and playing cricket and football (soccer), and listening to music.
I am now a hardware engineer at Apple in Silicon Valley, California, USA.